Does anyone know of where the above item for a 360 GLT can be purchased. I've looked on eBay but no luck

Try Brakes International, Rochdale, UK. They have a good webshop and if it isn't on that then a call or email will usually result in finding the parts.

Thanks ...will follow up with post
O

Scandix stock them

There are plenty of new/recon capilers around, so there must be seals about. Bigred are another good supplier, but I find the parts are very expensive, probably trying to encourage you to use their recon service.

http://www.biggred.co.uk/catalogue.php
£25 for 2 caliper kit.